(a) Contract provision.--A contract may include a provision for the retainage of a portion of the amount due the contractor to insure the proper performance of the contract except that the sum withheld by the government agency from the contractor shall not exceed 10% of the amount due the contractor until 50% of the contract is completed. When the contract is 50% completed, one-half of the amount retained by the government agency shall be returned to the contractor. However, the architect or engineer must approve the application for payment. The contractor must be making satisfactory progress, and there must be no specific cause for greater withholding. The sum withheld by the government agency from the contractor after the contract is 50% completed shall not exceed 5% of the value of completed work based on monthly progress payment requests. In the event a dispute arises between the government agency and any prime contractor, which dispute is based upon increased costs claimed by one prime contractor occasioned by delays or other actions of another prime contractor, additional retainage in the sum of one and one-half times the amount of any possible liability may be withheld until such time as a final resolution is agreed to by all parties directly or indirectly involved unless the contractor causing the additional claim furnishes a bond satisfactory to the government agency to indemnify the agency against the claim. All money retained by the government agency may be withheld from the contractor until substantial completion of the contract.(b) Department of General Services.--Notwithstanding subsection (a), when the Department of General Services is the government agency, the contract may include a provision for the retainage of a portion of the amount due the contractor to insure the proper performance of the contract except that the sum withheld by the department for the contractor shall not exceed 6% of the then total estimates until 50% of the contract is satisfactorily completed. The sum withheld by the department from the contractor after the contract is 50% satisfactorily completed shall not exceed 3% of the original contract amount. 1998, May 15, P.L. 358, No. 57, § 1, effective in 180 days.